Lubricating fluids containing 4, 4&#39;-bis(triorganosilyl) diphenylalkylamines



United States Patent 3,350,311 LUBRICATHNG FLUIDS CONTAINING4,4'-BIS(TRI- 0RGANOSILYDDIPHENYLALKYLAMINES Matthew J. Napoli, Chicago,Ill., assignor to Dow Corning Corporation, Midland, Mich., a corporationof Michigan No Drawing. Original application June 17, 1963, Ser. No.288,525, new latent No. 3,308,144, dated Mar. 7, 1967. Divided and thisapplication Nov. 9, 1966, Ser. No. 592,980

4 Claims. (Cl. 252-496) ABSTRACT OF THE DISCLGSURE Lubricating fluidsare stabilized by the addition of 4.4- bis(triorganosilyl)diphenylalkylamines.

This application is a division of application Serial No.

288,526, filed June 17, 1963, which is now US. Patent wherein R is amonovalent hydrocarbon group free of aliphatic unsaturation containingfrom 1 to 18 inclusive carbon atoms and R is an alkyl group containingfrom 1 to 18 inclusive carbon atoms.

The R groups can be any monovalent hydrocarbon radical free of aliphaticunsaturation containing from '1 to 18 carbon atoms. For example, R canbe an alkyl group such as a methyl, ethyl, propyl, butyl, amyl, hexyl,heptyl, octyl, decyl, dodecyl, pentadecyl, octadecyl, isopropyl,isob'utyl, tertiary butyl, or Z-ethylhexyl group; a cycloalkyl groupsuch as a cyclobutyl, cyclopentyl or cyclohexyl group; an aryl groupsuch as a phenyl, xenyl or naphthyl group; an aralkyl group such as abenzyl or 2-phenylethyl group; or an alkaryl group such as a tolyl,xylyl or mesityl group. Obviously in any one compound each R can be thesame or different groups. Particularly preferred compounds are those inwhich the R groups are phenyl and/or methyl groups.

The R group can be any alkyl group containing from 1 to 18 carbon atoms.For example, R can be a methyl, ethyl, propyl, isopropyl, butyl,isobutyl, tertiary butyl, ainyl, isoarnyl, hexyl, octyl, dodecyl,pentadecyl or an octadecyl group. Particularly preferred compounds arethose in which R is a methyl or ethyl group.

The compounds of this invention are prepared by first preparing a4,4-dilithiodiphenylalkylamine and then reacting this reagent with achlorosilane. The first reaction is represented by the equation:

The new compounds of this invention are obtained by reacting the abovedilithio derivative with a chlorosilane in accordance with the followingequation:

R and R in the formulae in the equations are as defined above.

Diethylether is a suitable solvent for both of the foreging reactions.The reactions are best conducted at reflux temperature.

The compounds of this invention, in particular the 4,4- bis(phenyldimethylsilyl) diphenyl-N-ethylamine; 4,4-bis(diphenylmethylsilyl)diphenyl-N-ethylamine and the 4,4- bis(diphenylmethylsilyl) diphenyl-N-methylamine, are useful as antioxidants for hightemperature lubricating fluids. From .2 to 5 percent by weight (based onthe weight of the lubricating fluid) of these compounds can be used tostabilize lurbicating fluids. These compounds are especially useful asantioxidants in trimethylolpropane triester fluids.

Now in order that those skilled in the art can better understand how thepresent invention can be practiced, the following examples are given byway of illustration and not by way of limitation. The following examplesare exemplary of the best method of the preparation of the compounds ofthis invention, however, other methods can be employed. In each example,the reaction was carried out in a nitrogen atmosphere.

Example I A 500 ml., 3-neck flask was equipped with condenser, stirrer,addition funnel and thermometer. 100 ml. of diethylether and 1.94 g.(0.28 gram-atoms) of lithium wire (cut into 112 pieces) were added. 20g. (0.056 mol) of 4,4-dibromodiphenyl-N-ethylamine was dissolved in 200ml. of diethylether and placed in the addition funnel. About 15 ml. ofthe 4,4-dibromodiphenyl-N-ethylamine ether solution was added to thereaction mixture with vigorous stirring and the reaction mixture heatedto reflux. Then 0.25 ml. of l-bromobutane and 0.5 ml. of ethyl bromidewere added to the reaction flask to initiate the reaction. The reactionmixture was kept at reflux for two hours. Heating was discontinued andthe reaction mixture was kept at reflux by addition of the balance ofthe 4,4'-dibromodiphenyl-N-ethylamine ether solution over a 20 minuteperiod. Upon completion of the addition the reaction mixture becameclear and Was then stirred for 30 minutes as the pot slowly cooled.

19.1 g. (0.112 mol) of dirnethylphenylchlorosilane was dissolved in 50ml. of diethylether and added over a 12 minute period from the additionfunnel. This brought the reaction to reflux again. Upon completion ofthe addition the reaction was stirred for 7 /2 hours and then filteredthrough glass wool to remove 0.29 g. (0.042 gram-atoms) of lithium. Thefiltrate (ether solution) was then poured into 500 ml. of an icesolution containing 0.5 mol. of NaOH for every one mol of NH Cl toseparate the organic liquid from the salt formed. The organic layer wasseparated and dried overnight over anhydrous sodium sulfate. The driedether solution was filtered through a Buchner funnel and then thesolvent was completely removed from the filtrate on a Rinco solventstripper, leaving a light yellow liquid. Distillation of the residue at0.90 mm. pressure gave 1.66 g. of a liquid boiling at 64 to 96 C.Further distillation at 0.40 to 0.26 mm. pressure gave 3.44 g. of aliquid boiling at to 184 C 3 There remained in the flask 17.7 g. ofresidue which crystallized to give a brown solid having a melting pointof 57 to 65 C. 16.3 g. of this solid was recrystallized from hot ethylalcohol to give 6.65 g. (25.5% yield) of a white solid with a meltingpoint of 63 to 65.5 C. This compound was identified as4,4'-'ois(phenyleimethylsilyl)diphenyl-N-ethylamine.

Example 2 To one liter, 3-neck flask equipped with condenser, stirrer,addition funnel and thermometer was added 100 ml. of diethylether and1.94 g. (0.28 gram-atoms) of lithium wire (cut into 100 pieces). Asolution of g. (0.056 mol) of 4,4'-dibromodiphenyl-N-ethylamine in 300ml. of diethylether was placed in the addition funnel. A few ml. of the4,4'-dibromodiphenyl-Nethylamine ether solution was added to the flaskwith vigorous stirring, stirring being continued for one hour. Then 0.5ml. of l-bromobutane was added and the mixture heated to reflux. Next0.25 ml. of ethyl bromide Was added and the refluxing continued for 45minutes. The remaining amine solution was then added over a 43 minuteperiod to maintain gentle reflux stirring was continued for minutesafter the completion of the addition.

A solution of 26 g. (0.112 mol) of diphenylmethylchlorosilane in 100 ml.of diethylether was then added reaction was then left to stir overnight.After stirring overnight, no trace of lithium was observed in thereaction mixture.

The reaction mixture was filtered and then the filtrate was poured into250 ml. of NH ClNaOH butler solution and 250 ml. of water to separatethe organic liquid from the salt formed. The organic layer was thenseparated and the solvent evaporated on a steam bath to give 34.3 g. ofa black oil. This black oil was taken up in boiling absolute alcohol,treated with Nuchar (activated charcoal), and filtered hot. Uponstanding overnight, small white crystals (M.P. 133-6 C.) began toseparate from the filtrate. Recrystallization of these crystals fromabsolute alcohol gave 1.75 g. (5.4% yield) of a white crystalline solid(M.P. 1368 C.). This solid was identified as 4,4'-bis(methyldiphenylsilyl) diphenyl-N-methylamine.

Example 4 The compounds of Examples 1 and 2 were found to possessantioxidant properties when one percent by weight of them was added to atrimethylolpropane ester fluid and tested therein.

Example 5 The following products are obtained when the followingreactants are reacted in accordance with Example 1 and at the same moleratios as in Example 1.

Reactants Product Dilithio Derivative ol Silane4,4-dibromodiphenyl-N-isopropylamine..

4,4-dibromodiphenyl-N-oetadeeylamine.

Diphenylpropylchlorosilane,4-bis(tripheny1silyl)diphenyl-N-isopropylamine.

4,4-dibr0modiphenyl-N-hexylamine 4,4 -bis (t rimethylsilyl) diphenyl-N-hexylamine. 4,4-dibromodiphenyl-N-octylamine- 4,4J-bis(decyldiphenylsilyl) diphenyl-N-octylamine.4,4-dibromodiphenyl-N-butylamine.4,4-bis(cyclohcxyldiphenylsilyl)diphcnyl-N-butylamine.4,4-dibromodiphenyl-N-ethylamine 4,4-bis (henzyldiphenylsilyl)diphenyl-N-ethylamine. 4,4-dibro1nodiphenyl-N-ethylamine4,4-bis(diphenyloctylsilyl)diphenyl'N-ethylarnine.4,4-dibromodiphenyl-N-ethylaminc Diphonyltolylchlorosilane..-4,4-bis(diphenyltolylsilyl)diphenyl-Nethylan1ine.4,4-dibromodiphenyl-N-dodeeylaniinc. Di1)henylethylchlorosilane4,4-bis(diphenylethylsilyl)diphenyl-N-dodecylamine.4,4-dibrom0diphenyl-N-ethylamine Diphenyloctadecylehlorosilane 4,1-bis(diphonyloctadceylsilyl)diphenyl-N-ethylamine.

4,4-bis(diphcnylpropylsilyl) dipheuyl-N-oetadccylarnine.

through the addition funnel over a minute period to maintain reflux. Thereaction mixture was then stirred for one hour at room temperature andfiltered through glass wool to remove 0.40 g. of unreacted lithium. Thefiltrate was then poured into 500 ml. of NI-LgCl-NaOI-I buffer solutionto separate the organic liquid from the salt formed. The organic layerwas separated and dried over anhydrous sodium sulfate. The dried ethersolution was filtered and then the solvent removed to obtain 33.1 g. ofa light yellow to green oil which solidified upon standing. 8.49 g. ofthe solid was recrystallized twice from absolute alcohol with 7.91 g.(23.9% yield) of a white solid, M.P. 1313 C., being obtained. This solidwas identified as 4.4'-bis (methyldiphenylsilyl) diphenyl-N-ethylamine.

Example 3 To a one liter 3-neck flask equipped with condenser, stirrer,addition funnel and thermometer was added 50 m1. of diethylether and1.94 g. (0.28 gram-atoms) of lithium wire (cut into 70 pieces), and 90ml. of tetrahydrofuran. 19.1 g. (0.056 mol) of 4,4-dibrornodiphenyl-N-methylamine dissolved in 300 ml. of diethylether and 65 ml. oftetrahydrofuran were added to the flask. Then 26 g. (0.112 mol) ofdiphenylmethylchlorosilane was added and the reaction left to stir.After stirring 5 minutes the pot temperature rose to approximately 50 C.The

That which is claimed is: 1. A lubricating fluid containing 0.2 to 5percent by weight of a compound of the formula UNITED STATES PATENTS2,960,517 11/1960 Schnabel 252-49.6 X 3,065,251 11/1962 Jones et al. 25249.6 X

DANIEL E. WYMAN, Primary Examiner.

PATRICK P. GARVIN, Examiner.

W. H. CANNON, Assistant Examiner.

1. A LUBRICATING FLUID CONTAINING 0.2 TO 5 PERCENT BY WEIGHT OF ACOMPOUND OF THE FORMULA